*Writing these oneshots fills you with Determination (Undertale AU Oneshots)

♦ Close (Gaster x Reader)

*This one's a bit long. Sorry!

As you yawned, you rubbed your eyes, feeling them tear up. "Ugh... Gaster, I'm tired and I know you are too," you grumbled, taking a lazy sip of your coffee, "Can we please go to sleep?"

"Not yet, I'm close to a breakthrough, I can feel it," he said tiredly, even though he didn't express it in his voice.

"That's what you said 2 hours ago. And then, it was midnight! I just don't understand why you insist on finding a solution when you've hadn't made any progress in the past few days."

"Obviously."

You rolled your eyes and sighed, laying your head on the desk he was working on. "Whatever." You started leaving the room.

You and Gaster have been living together for a few months now, and you feel as if you've gotten somewhat close. Actually, no. It's nowhere near close. It's somewhere in between 'Hate' and 'Tolerate.' Although you felt like it's been more than 'Tolerate.' Maybe 'Aware of each other's existence.' Yeah, that's it. You didn't exactly 'dislike' him per se, he could just be impossible sometimes, and you knew for a fact, even if he didn't come out and say it, you could be the same way to him. But you thought of you two as cool friends if he'd let you refer to him like that.

"Gaster?"

"If this is about anything you've said a few minutes ago, then please refrain from expressing it again," he replied as he observed whatever was under his microscope.

"Yeah, it is, actually. But I'll still say it. Look, I understand that you're trying to find a solution for the CORE but-"

"______..." he tried to stop you but you kept talking.

"-you've gotta consider if it doesn't work, what then? I'm sorry, but that's just how things work..." You were kinda worried he wouldn't listen to you, but then again, you wouldn't be surprised.

Suddenly, a purple aura surrounded you and you were roughly put against the wall, gasping for air.

Gaster approached you and glared at you with slight annoyance. "Child," he started in a low, cold voice, "I am aware of the margins of error in this experiment, and I don't need to be reminded of how things in life work, especially from a juvenile human who I was foolish enough to let stay in my home for longer than mutually beneficial." He gave you a mean, sarcastic smirk.

You froze at his words, staring at him with widened eyes.

"Now, if you'll excuse me, I have a CORE to repair. If you want to waste your time sleeping your life away, then by all means, do so. Besides," he went back to examining a blueprint of the CORE, "Asking for your assistance with a delicate project such as this is futile."

As you were released from the hold of his magic, you silently trailed to the exit. Taking deep breaths, you were careful not to raise your voice. "And here, I thought it was a good idea to actually care about you a little."

He didn't seem fazed by your words, not that you expected him to be, but just continued his work. "How wrong of you," was all he replied under his breath, purposefully making it audible enough for you to hear.

You shot daggers at him and stormed out, upset that you couldn't adequately express how angry you were. Dashing to your room, you slam the door and punch the wall beside it. Feeling tears prick at the corners of your eyes as a result of the pain in your fist, you grunted frustratedly and tried to calm yourself down.

"Ugh! That dysfunctional, conceited, vexing son of a biscuit!" You hit your head against the wall, trying to relieve yourself of your anger... it didn't help. At all.

You never liked being angry, especially when you knew you'd regret it afterward. It made you feel strange like it was wrong. There was this dormant side of you finally coming out and you hated it. What confused you, even more, was that you never let the things that people said get to you, let alone Gaster! You didn't know if it was just something about him specifically that annoyed you or...

"Alright. Calm down, _____. It's just words. Meaningless, stupid words," you consoled yourself as you rocked back and forth on your bed. What Gaster said replayed in your mind and you couldn't help but grind your teeth, making your self-comfort kind of trivial.

Suddenly, you hear a loud knock on your door, making you flinch a bit. Your brows furrowed, for you knew exactly who was knocking. You didn't want to see him right now, honestly; you didn't have enough time to cool off.

"What do you want?" you snapped curtly, not moving from your spot on the bed.

"Would you let me in?" Gaster answered, avoiding your question.

You groaned and rolled your eyes, begrudgingly getting off the bed and going to open the door.

Standing there, nice and straight was Gaster, his face firm but somewhat... soft? He let himself in, taking no mind to you consenting him to come in, and stood himself in the center of your bedroom.

You couldn't help but blush a little, as your room wasn't usually a place Gaster visited often, let alone scanned and observed closely. Though you were surprised he didn't make some snarky or belittling comment about your choices of decoration for your room, so you saw fit to listen to him for once.

"Are you gonna explain why you're here or are we just gonna stare at each other like idiots?" you asked sarcastically, crossing your arms.

He gave you a look, but not a condescending look or one of annoyance; More like... lament? By this point, you were majorly confused. Why was he acting so weird?

"I am aware of the intensity of the words that were spoken a moment ago, and that I have ignored how they might have influenced you to feel negligible in some way," he stated plainly, staring you in the eyes.

"And by negligible, you mean that they pretty much made me want to put my fist through the wall," you replied nonchalantly, glaring at him.

"...Yes. It has occurred to me that I have perhaps been a bit caustic over the course of the week... And for that, I give you my apologies." He bowed his head regrettably.

You shivered at his words, slowly uncrossing your arms. "You what?" you questioned him, not completely processing his words.

"For God's sake, you heard exactly what I said," he spat, clenching his fists slightly.

'At least he hasn't lost his attitude,' you thought, taking a couple steps towards him.

"And I also apologize for threatening you and using my magic to throw you against the wall. Although it doesn't seem like it, I do listen to you and hear what you say about using up all my energy on magic attacks... and I won't be doing it again."

You looked at him, your expression softening a bit. You still must've had a stern look on your face, though, because Gaster's cheekbones turned to a light hue of purple and he seemed a bit uneasy. He cleared his throat uncomfortably.

You didn't know which was more unbelievable, the fact that he listens to you, or the fact that he was using overly-big words just to say 'sorry.'

Thoughtlessly, you quickly wrapped your arms around him in a tight embrace with a bright blush on your face. You didn't know what you were doing, but you didn't want to stop. You felt Gaster tense up under your touch, but he soon relaxed and awkwardly patted your head with one hand, using his other arm to loosely hug you back.

"I forgive you," you said under your breath, but loud enough so that he could hear.

Gaster chuckled nervously, obviously uncomfortable with this position. For lack of better words to say, all he managed to say was, "...Well, good... Thank you."